1. Field of the Invention
This invention relates to a method for making an opening in a bladder of an inflatable modular structure for receiving a window. The inflatable module structure is a versatile device for use in space and can be employed as a space based habitat. The structure is capable of being collapsed before being launched into space and then once deployed into space, the structure expands for use as a space based module. In the case where the module houses crewmembers, viewing windows are usually employed to see outside the module. The present invention is directed to a method of making an opening to receive such windows.
2. Description of the Prior Art
Space based modular human habitats are well known and inflatable modular structures for space are typified, for example, by U.S. Pat. No. 6,439,508 to Taylor, U.S. Pat. No. 6,231,010 to Schneider, et al, and U.S. Pat. No. 6,547,189 to Raboin, et al.
When crewmembers are present in a deployed module, it is important to have windows for the crewmembers to see through. This has both practical and psychological advantages.
As a practical matter, the crewmembers can view conditions external to the module. This is important when, for example, work is being performed outside the module and the crewmembers inside the module are assisting by monitoring the progress of the tasks performed external to the module.
While television cameras could be employed to perform the same function, the exclusive use of television cameras is not desirable. For example, when crewmembers are on long term assignments within a module without windows the crewmembers are effectively in an environment without a visual connection with the outside world or space. This form of sensory deprivation can have a negative impact on the crew's psychological well being.
The use of windows in a space module is not new or novel. However, placing a window in an inflatable modular habitat presents unique challenges that have no parallel when working with a solid module.
A solid shelled module is not likely to change its shape significantly when deployed into space. As a result, a window location can be easily identified on a solid shell and a window installed without the shell changing its shape. Once deployed, the window in the solid shell would be in the same location as when the window was installed on the ground.
While this is generally true even if there are layers on the surface of the solid shell, this is not the case for an inflatable module.
The shell of the inflatable module is malleable and is generally comprised of a number of layers. There is usually at least a bladder, a restraint layer, and a meteor debris shield. All of which are flexible to accommodate being collapsed for launch and inflated in space and all must have an opening so as not to obstruct the view from a window.
Another difficulty arises when installing a window that integrates with the bladder. The extent to which the bladder is inflated is at least partially dictated by the flexible restraint layer. The restraint layer serves to distribute the load from the bladder to the rigid structural core of the module and provides the outer boundary for the limit to which the bladder can distend.
If the window was attached only to the bladder, then expansion of the bladder could bulge the window out beyond the limit of the restraint layer. This would stress the bladder and could potentially cause a rupture. This is not desirable so it follows that the window must be integrated with both the bladder and the restraint layer to prevent such bulges.
What is needed is a method of making an opening in the bladder of an inflatable modular structure such that an opening in the flexible restraint layer and the opening in the bladder coincide an are used in combination for supporting a window.
The present invention may be best understood by reference to the following description taken in conjunction with the accompanying drawings.